This application claims the priority of German patent document 198 23 708.1, filed May 27, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an identification system for the user of a vehicle, having a mobile transponder which contains a memory for an authorization code and a transmitting-receiving device for transmitting the authorization code to a vehicle-fixed receiver.
Identification systems of this generic type area generally known. The transponder is preferably connected with a mechanical key to form a modular unit. In addition stand-alone systems are known, such as disclosed for example in European Patent 452 346 B. Such systems are often called keyless entry or passive entry systems.
The known devices can be lost relatively easily and fall into the hands of an unauthorized user. This creates the considerable danger that the safety measures inherent in these devices are counteracted by minor carelessness.
It is an object of the invention to provide a system of the initially mentioned type which can be handled easily while its safety with respect to a loss is high.
This and other objects and advantages are achieved by the identification system according to the invention, in which the transponder is arranged in a user""s wristwatch, and thus demands no additional attention. Since virtually everyone wears a wristwatch and is accustomed to it, a loss will be rapidly noticed and precautions can be taken so that the vehicle will not be used.
An advantageous embodiment of the invention includes a means for supplying such a system with energy. This embodiment not only has the advantage of low constructional expenditures but also the characteristic that, if it is removed from one wristwatch and inserted in another, it can erase the data content, provided it is situated in a volatile memory.
A further feature of the invention relates to the assignment of the transponder, the wristwatch and the vehicle. A problem occurs if the wristwatch with a transponder, which is fixed with respect to its data content, is used for access and driving authorization for the vehicle. The clearing and blocking of the watch only at the vehicle (that is, in connection with vehicle usage operations) represents a weak point with respect to protection against theft, because it would then be possible for an unauthorized user to read in the data content of his watch unnoticed by the authorized user and thereby procure access authorization for himself. The (authorized) user can also not be expected to hand over the wristwatch when he sells the vehicle.
Another embodiment of the invention provides a solution for this problem, in that the watch and the transponder can be separated from one another. When selling the vehicle, the user can thus keep the watch. This results, however, in the problem of synchronizing to another vehicle. This problem is basic and exists when the vehicle is first operated. It can be solved, however, as follows:
The user can buy a transponder, which is provided with a vehicle-individual authorization code, that is, it is, for example, programmed by means of vehicle data which can be obtained from the vehicle dealer under the same conditions under which he receives a replacement key (for example, by presenting his identification card and vehicle papers). He can buy the corresponding wristwatch at a store specializing in clocks and watches. It is important in this case that the watch is provided with an individual identification code, such as a factory designated PIN-number or, for example, a serial number. When the user now snaps the transponder into the watch (for example, into a container in the battery compartment) by means of a contact, the transponder is supplied with energy from the energy accumulator of the watch. Then the identification code is automatically read out of the logic part of the watch, and is filed in the transponder in a volatile memory (RAM).
This watch can then be assigned to the vehicle. For example, by means of a mechanical vehicle key, the vehicle is opened up and started and subsequently a transponder query is started. The transponder will then transmit the identification code in addition to its authorization code, both of which are stored in the vehicle. When, at the time of another access, the two codes are transmitted, the vehicle recognizes the user as being the authorized user. The described identification of the user is secure with respect to unauthorized manipulations because the storage of the identification code will take place only if, together with it, the vehicle-individual authorization code is also transmitted.
Although the content of the volatile memory will be lost when the energy accumulator of the wristwatch is changed, access to the vehicle is possible in the above-described manner without hindrance. When the energy accumulator of the watch is activated, the identification code is read into the RAM of the transponder. Upon a query by the vehicle, this identification code is read out of the transponder, together with the authorization code, and is recognized in the vehicle by means of the identification code, known from the earlier synchronizing operation, which continues to be held there.
When the vehicle is sold, the transponder is transferred to the new owner, who can insert it into his wristwatch having an individual identification code. By means of the mechanical key, the new user proves his access authorization. Since previously, when the transponder was inserted, the identification code was read into the RAM of the transponder, during the query by the vehicle, this identification code, together with the unchanged and still valid authorization code, can be read out of the transponder and stored in the vehicle.
According to another feature of the invention, the time indicated on the wristwatch can also be transmitted by the transmitting-receiving device, and can be fed into a synchronizing device of the vehicle clock.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.